<!DOCTYPE html>
<html>
<head>
	<title>Boolean</title>
</head>
<body>
<script type="text/javascript">
	
	// 五种数据转换为Boolean，值为false，其余全为true
	console.log(Boolean(''))		// false
	console.log(Boolean(null))
	console.log(Boolean(undefined))	// false
	console.log(Boolean(0))			// false
	console.log(Boolean(NaN))		// false
	console.log(Boolean(-1))		// true

</script>
</body>
</html>